A chemical accident is the unintentional release of hazardous substances that can harm human health or the environment through fires, explosions, leaks or toxic releases. While chemical accidents can occur anytime toxic materials are handled, the most severe accidents tend to be large-scale industrial incidents. The 1984 Bhopal disaster in India, which killed over 3,000 people, remains the worst industrial accident in history due to a leak of methyl isocyanate gas at a Union Carbide pesticide plant.

2. A chemical accident is the unintentional release of one or
more hazardous substances which could harm human health
or the environment. Chemical hazards are systems where
chemical accidents could occur under certain circumstances.
Such events include fires, explosions, leakages or releases of
toxic or hazardous materials that can cause people illness,
injury, disability or death.
While chemical accidents may occur whenever toxic
materials are stored, transported or used, the most severe
accidents are industrial accidents, involving major chemical
manufacturing and storage facilities. The most significant
chemical accident in recorded history was the 1984 Bhopal
disaster in India, in which more than 3,000 people had died
after a highly toxic vapour, (methyl isocyanate), was released
at a Union Carbide Pesticides factory.

3. HUMAN ERROR
A majority of the industrial accidents that occur every year are a
result of human error. Many of these accidents are a result of the
worker failing to follow the safety procedures that have been put
into place by the company where he or she works. As of 2009, a
majority of industrial injuries (74.8%) happened in the service-
related industry, according to the Bureau of Labour Statistics.
When the proper equipment is not used by personnel, accidents
can occur. Many injuries happen when personnel attempt to use
improper tools to work on equipment. This can damage the
machines and create a safety hazard.

4. IMPROPER TRAINING
When personnel are not trained properly or adequately,
industrial accidents are more likely to occur. Workers should
be taught how to operate the equipment in the way it was
designed to be used. They should also learn to employ
correct safety procedures when they are operating the
equipment. Employees should be well versed in what to do if
something goes wrong so that they can work to correct the
problem quickly before it gets out of control.
During 2009, 4.3 out of every 100 workers in the
manufacturing industry were involved in industrial accidents.
A majority of these accidents occurred as a result of improper
training of personnel

5. MANUFACTURING DEFECTS
Accidents that occur in a chemical plant can also be the result of a
manufacturing defect. These defects can be present in a piece of
equipment or in the materials used. Although companies employ
several quality-control measures during the manufacturing process,
some of these may fail. This is because many of these control
measures are handled by employees. Where humans are involved
there is always a chance of human error. An inspector may miss a
defect that occurred during manufacturing. The problem may not be
recognized until after an accident has occurred.

6. IMPROPER MAINTENANCE
A common reason that industrial accidents occur in chemical
plants is the improper maintenance of equipment. Regular
maintenance at scheduled intervals following the manufacturer’s
recommendations is important for ensuring that the equipment
runs smoothly and safely. When a piece of equipment is not
properly maintained, it can malfunction and ultimately fail. This
can result in dire consequences to the personnel who are
operating and working around the machine.

7. Equipment failure
The use of inappropriate equipment is a big contributor to
chemical accidents as it leads to the equipment
malfunctioning. This includes use of inappropriate
chemical storage – non-flammable units used to store
flammables for examples, containment barriers or spill kits
not being used correctly or failing to fulfil their purpose,
check valves malfunctioning as they are not suited to the
purpose intended and the use of pressure relief systems
which are not adequate to relieve the level of pressure
flow.

8. Warnings ignored
Many large scale chemical accidents come as a result
of ignoring warning signs such as smaller chemical
incidents, spills or injuries. Minor chemical spills are
merely cleaned up so that operations can continue
without the source of the spill or leak being fully
investigated or remedied leading to an even larger
scale chemical spill in the future. Personnel are not
made aware or cautioned in relation to mistakes they
have made when handling or storing chemicals
therefore they continue to make the same mistakes,
often resulting in a chemical accident. Minor chemical
combustions are not properly investigated and therefore
root causes such as improper chemical storage are not
identified until after a major chemical explosion. These
are just some of the many examples of how ignored
warnings have led to significant chemical incidents.

9. Major accidents involving chemical substances have local
effects, but in exceptional circumstances they can affect
whole regions because of weather conditions. Scientific
technical developments have made it possible to prevent
such dangers and therefore to protect people from them. The
priority must be on prevention, but a positive result can only
be assured if there are strict guidelines for using and handling
these products, as well as professional knowledge, both of
which are indispensable in this very complex field.

10. When an accident involving chemical substances that could endanger
life or the environment occurs in a chemical works or installation, those
in charge of it should immediately take the following planned
measures:
- Deal with the causes of the accident and implement the safety
measures which will minimise its consequences.
- Immediately inform the relevant local authorities of the accident.
- The local or regional authorities of the area in which the installation is
located are responsible for informing the public, sounding the alarm if
need be, and deciding upon the instructions to be followed by the
population. The local or regional governing body ensures the co-
ordinated use of the civil and military means required to deal with the
disaster. In the case of radioactivity, the technical co-ordination of the
implementation of protective and rescue measures is assured by
specialists who should be present at all political levels and in all the
intervening squads, and work in collaboration with the personnel in
charge of security at the installation affected.

11. The Bhopal disaster, also referred to as the Bhopal gas tragedy,
was a gas leak incident on the night of 2–3 December 1984 at the
Union Carbide India Limited (UCIL) pesticide plant in Bhopal,
Madhya Pradesh, India. It was considered as of 2010 to be the
world's worst industrial disaster.[1]
Over 500,000 people were exposed to methyl isocyanate (MIC)
gas. The highly toxic substance made its way into and around the
shanty towns located near the plant.[2]
Estimates vary on the death toll. The official immediate death toll
was 2,259. The government of Madhya Pradesh confirmed a total
of 3,787 deaths related to the gas release.[3] A government affidavit
in 2006 stated that the leak caused 558,125 injuries, including
38,478 temporary partial injuries and approximately 3,900 severely
and permanently disabling injuries.[4] Others estimate that 8,000
died within two weeks, and another 8,000 or more have since died
from gas-related diseases.[5]

12. The cause of the disaster remains under debate. The Indian
government and local activists argue that slack management
and deferred maintenance created a situation where routine
pipe maintenance caused a backflow of water into a MIC
tank, triggering the disaster. Union Carbide Corporation
(UCC) contends water entered the tank through an act of
sabotage.

13. The owner of the factory, UCIL, was majority owned by UCC,
with Indian Government-controlled banks and the Indian
public holding a 49.1 per cent stake. In 1989, UCC paid $470
million ($907 million in 2014 dollars) to settle litigation
stemming from the disaster. In 1994, UCC sold its stake in
UCIL to Eveready Industries India Limited (EIIL), which
subsequently merged with McLeod Russell (India) Ltd.
Eveready ended clean-up on the site in 1998, when it
terminated its 99-year lease and turned over control of the
site to the state government of Madhya Pradesh. Dow
Chemical Company purchased UCC in 2001, seventeen
years after the disaster.

14. Top 10 Chemical
Accidents
Feyzin Explosion, France (1966)
Flixborough, UK (1974)
Seveso, Italy (1976)
San Juanico LPG Disaster, Mexico City (1984)
Bhopal, India (1984)
Schweisehalle, Switzerland (1986)
Baia Mare Cyanide Spill, Romania (2000)
Enschede Fireworks, Netherlands (2000)
Grande Paroisse Fertilizer Plant Explosion,
France (2001)
Texas City Refinery Explosion, Texas, USA
(2005)